Taiwan sent ships and fighter jets to monitor the second Chinese "joint combat readiness patrol" in a week near the island, in what a senior Taiwanese security official said showed China was the sole source of instability in the region.
China has pressured Taiwan by increasing its military presence around the island, and Taipei is on high alert for further Chinese actions after President Xi Jinping discussed Taiwan with US President Donald Trump in Beijing this month.
China views democratically governed Taiwan as its own territory, and operates its warships and warplanes around the island on an almost daily basis. Taiwan's government rejects Beijing's sovereignty claims.
Late on Monday, Taiwan's defence ministry said it had detected 21 Chinese aircraft, including J-16 fighters and drones, operating all around the island, which, along with warships, were carrying out a "joint combat readiness patrol".
China's defence ministry did not immediately respond to a request for comment.
Taiwan's defence ministry published three pictures taken by its own forces - one from an F-16 jet of two Chinese fighters trailing a Y-20 aerial refuelling aircraft, one of the Chinese warship the Yinchuan, and one of a Taiwanese navy sailor watching the same ship through binoculars.
Writing on his social media account on Tuesday about the patrol and presence of the Liaoning carrier group, Taiwan National Security Council Secretary-General Joseph Wu said what China was doing was, "unprovoked."
"The PRC is the sole source of instability in the Indo-Pacific," he added, referring to the People's Republic of China.
On Saturday, Wu said China had deployed more than 100 ships up and down the first island chain, an area that stretches from Japan down to Taiwan and into the Philippines. Those ships remain in place, a separate Taiwan official told Reuters.
Speaking to reporters in Taipei, Pan Chun-kuang, from the ministry's intelligence department, said Taiwan also continues to track the movements of China's aircraft carrier, the Liaoning, operating in the Western Pacific.
China carried out a similar "readiness patrol" last Tuesday, the day before Taiwan President Lai Ching-te marked his second year in office. China calls Lai a "separatist" and has rebuffed multiple offers from him for talks.
Su Tzu-yun, a director at Taiwan's top military think tank, the Institute for National Defence and Security Research, said Chinese warships equipped with cruise missiles are being deployed as close as 24 nautical miles from Taiwan's shores during these "combat" patrols.
That gives air defence forces far less time to respond, especially because ship-launched, sea-skimming missiles are harder to detect and could hit targets just three minutes after being launched.
"If China were to use this kind of surprise missile attack, it could temporarily paralyse Taiwan," he added.
Over the weekend, Taiwan said its coast guard had faced off with a Chinese coast guard ship near the Taiwan-controlled Pratas Islands, which are strategically located at the top end of the South China Sea.
(Reporting by Ben Blanchard and Yimou Lee; Additional reporting by Yi-Chin Lee, Fabian Hamacher and Roger Tung; Editing by Lincoln Feast, Himani Sarkar and Thomas Derpinghaus)
